LiAlH₄ (LAH)cannot be used to convert carboxylic acids to the corresponding aldehydes because: A)LAH is not sufficiently reactive. B)RCOOH is converted into RCOOLi. C)RCOOH is reduced to RCH₂OH. D)RCOOH is reduced to RCH₃. E)RCOOH is converted into R₂C=O.

Question

Quizplus · Accepted Answer

LAH is a very strong reducing agent that can reduce carboxylic acids to primary alcohols (RCH2OH) or even further to aldehydes (RCHO) and then to primary alcohols. However, in the presence of LAH, carboxylic acids do not undergo conversion to aldehydes. Instead, they are converted to RCH(SH)OH, which is a thiol. This happens because LAH reduces the carbonyl group of the carboxylic acid to an aldehyde, but at the same time, the hydrogen on the alpha carbon is also reduced to a hydride ion (H-). The resulting hydride ion reacts with the aldehyde to form the corresponding thiol.

LiAlH4 (LAH)cannot Be Used to Convert Carboxylic Acids to the Corresponding

LiAlH₄ (LAH)cannot Be Used to Convert Carboxylic Acids to the Corresponding